Method for producing a tag or a chip card, device for implementing said method and tag or chip card produced according to said method

ABSTRACT

A method for manufacturing a tag encompassing an antenna or coil that is capable of at least one of wirelessly transmitting information to remote receivers and receiving information from remote transmitters. The method includes die-cutting a coil or antenna shape from an electrically conductive flat double foil having an upper electrically conductive flat foil layer of a soft, inelastic metal and a lower synthetic film substrate layer, the die-cutting including cutting with a die-cutting tool having a single die-cutting blade which matches the desired antenna or coil shape, the blade completely perforating the upper electrically conductive flat foil and at least partially separating the lower synthetic film substrate so that a gap the distance created in the flat foil by die-cutting remains after the die-cutting tool is removed. Subsequently the cut shape is bonded with additional layers including an electronic chip module.

[0001] The present invention concerns a method for manufacturing a tagwhich encompasses an antenna or a coil, the same said method formanufacturing a chip card or an identification card or a similartransponder unit in accordance with the first part of the independentclaim 1, an apparatus for executing the method in accordance with thefirst part of the independent claim 6, and a tag encompassing an antennaor coil or a corresponding chip card in accordance with the first partof the independent claim 7.

[0002] Chip cards or identification cards encompassing an antenna or acoil or similar small-scale assemblies such as for instance tags,transponder units and the like, are known in a multiplicity ofembodiments. They generally serve to receive wireless information and,in some cases, to process it, but also to transmit information, forinstance concerning the location, the properties of the objectsconnected to it and similar information (back) to the appropriatereceivers.

[0003] In addition to many other areas of application, the use ofso-called tags is becoming increasingly important, for instance forbaggage sorting at airports, where hundreds of thousands of suitcasesare conveyed to their correct destinations using automatedtransportation systems, as well as for postal items, where they makeautomated sorting possible. To achieve this, specific address codes areentered into the tags and the tags are then attached to the particulargoods, with the tags wirelessly conveying relevant information to anyinquiry units along the automated transportation route, so that forinstance, switching units or distribution belts or sorting devices alongthe transportation route can respond.

[0004] In order to receive or transmit such information wirelessly, suchtags, as they shall be known representatively for all other assembliescontaining antennas or coils, chip or identification cards, transpondersor the like, all require coiled, wound or meandering lengths of wire insome helical form for receiving or transmitting electromagnetic signals,which are usually in a digitally encoded form.

[0005] However, when attaching or applying such coils or antennas toeach substrate, there are certain problems that significantly increasethe cost of such tags that are now required in their millions. Thismeans that the commonly used etching technique, with which single coilconnections can be applied to chip-card foil substrates (EP 0 481 776A2), requires numerous additional processing steps. In particular, theseinvolve the application of photoresist to vapour-deposited or otherwiseapplied conductive layers, then their exposure using masks and theremoval of intermediate layers by means of etching, all of which makethe production of such tags considerably more expensive, especially whenone considers the large number of units common in this field.

[0006] Turns of the coil are also known that are basically wire windingsattached in the form of a continuous winding on a synthetic substratewith the aid of complex wiring and cutting machines, whereby thesynthetic substrate is heated thermally at the same time in such a waythat the turns of the wire bond at least partially with the heatedsynthetic substrate material and in this way retain their shape at leastuntil further layers can be applied (U.S. Pat. No. 3,674,602,international PCT application WO 95/26538).

[0007] Both methods of attaching the wire are complicated as well astime-consuming, with WO 95/26538 also proposing that the coil wire beconnected to the first terminal pad of a chip located on the chip cardat the same time as it is being laid. Then the coil wire is laid tocreate the coil and finally the running end of the coil wire isconnected to a second terminal pad on the chip, whereby the wire isconnected at least partially to the substrate during the laying of thecoil wire as a consequence of the substrate being heated.

[0008] It is thus the aim of this present invention to propose a methodwith a device for producing a tag that encompasses an antenna or a coilor some other arrangement that not only drastically simplifies butsubstantially minimises the costs involved in producing and arrangingthe coil on the tag or chip card in this way.

[0009] The invention provides a solution by means of the distinctivefeatures presented in claim 1, claim 6 and claim 7, which concerns thetag itself.

[0010] A particular advantage offered by the present invention resultsfrom the fact that only one single additional production step isrequired for the preparation of the coil or antenna during the automatedproduction of such tags or chip cards, namely a die-cutting process.

[0011] This die-cutting process allows the antenna to be produced in anyshape, also ones which match the shape of the tag; this means that inthe preferred and therefore also the simplest embodiment, nopost-processing steps are required.

[0012] The entire process of manufacturing the coil or antenna occursduring the in-line automated tag production operation without anyspecial additional steps and consists solely in a conductive foil beingadded, commonly a copper or aluminium foil applied to the supportingsubstrate, and a die-cutting tool cutting the desired antenna shape(spiral, rectangular, meandering or any other shape) into thecopper-coated foil in a cutting process. Additional processingoperations are not required as a result of the specific properties ofthe copper or aluminium foil which allow a functional antennaconfiguration to be immediately created on a supporting substrate. Afterthis stage, the chip is connected in the customary manner and thenpreferably, the finished tag is achieved by means of additional layersbeing applied in a bilateral lamination process.

[0013] If the preferred embodiment of the present invention is employed,no die-cut parts have to be removed during the die-cutting process inorder to produce the antenna, a process which would necessitateemploying an additional operation involving a gripping action—a singledie-cutting process is sufficient, for instance in a spiral shape, inorder to immediately produce a spiral wound antenna on the copper-coatedsubstrate, the two ends of which only need to be attached to therespective chip module, for instance by crimping or soldering ifdesired.

[0014] In actual fact, one of the main features of the invention isbased on the realisation that by employing a special original material,namely a substrate with a conductive coating and preferably consistingof a synthetic material, such as for instance a copper-coated polyesterfilm, the adjacent turns of the copper spiral formed during thedie-cutting process can be electrically isolated effectively so that nofurther additional processing steps are necessary. The reason for thisshall be explained in more detail below.

[0015] It must be pointed out once again that the invention is suitablefor producing or for installing into any transponder-type systems,units, tags, chip or identification cards, access cards or keys, creditcards and the like, whereby the following text refers only to tags,being representative of all such systems; in the same manner the termantenna is used to designate any configurations of coil structures orother coils with turns wound around each other in the form of a winding.

[0016] Not only does the invention make it possible to manufacture suchtags, which are now required in great numbers, considerably faster incomparison with, for instance, the step-by-step wire application methodinvolving intermediate attachments in accordance with both thepublications cited at the outset, but also substantially reduces thenumber of processing stages required in comparison with the knownetching method. In this way and in conjunction with the structuralsimplification, it represents an effective reduction in costs.

[0017] Modifications and refinements to the invention constitute thesubject matter of the sub-claims or can be found in the followingdescription.

[0018] Embodiments of the invention are shown in the drawing and shallbe presented in more detail in the description below.

[0019]FIG. 1 shows a schematic top view of a first embodiment of acopper or aluminium coated substrate foil for the manufacture ofantennas;

[0020]FIG. 2 shows a schematic and greatly magnified lateral view of acopper or aluminium foil applied to a synthetic substrate film beforeand after the die-cutting procedure by means of a die-cutting tool shownin schematic form;

[0021]FIG. 3 shows a second embodiment of a spiral-shaped die-cutincision in the flat foil of a conductive material, with or withoutadditional substrate; and

[0022]FIG. 4 schematically shows a possible automated production chainfor tags.

[0023] The basic idea behind the present invention is to create anextended sequence of antenna or coil windings or turns by die-cuttingthese from a flat layer of electrically conductive material, wherebysaid windings or turns can be employed in the manufacture of tags orgenerally in the manufacture of transponder-type assemblies.

[0024] The preferred embodiment of the invention shall be describeddirectly below in greater detail, whereby the basic material for themanufacture of the antenna is a flat foil of electrically conductivematerial, commonly copper or aluminium foil, which is applied orlaminated onto a supporting substrate, preferably a synthetic film suchas polyester.

[0025] The thickness of such a polyester film can for instance rangebetween 50 and 250 μ, but can be set at any thickness as required, inthe same manner as the thickness of the copper foil used for the actualmanufacturing process is of subordinate significance and can be derivedfrom the other parameters (such as the transmitting power) of such atag.

[0026] In FIG. 1 the double-layered original material in the form of adouble foil is indicated by the number 10; it consists (FIG. 2) of an(upper) copper foil 11 and the lower, synthetic film substrate 12.

[0027] In order to manufacture an antenna or a coil with a large numberof turns from such a double foil 10 by means of die-cutting, a cuttingtool is required that has a correspondingly shaped blade.

[0028] This blade can have a cross-section that is shaped as shown inFIG. 2 by object 13; it can either taper to a point or be of equalthickness across the entire width of the double foil 10 comprising thetwo layers 11 and 12, a fact which is of little significance to thedie-cutting process. One can imagine a suitable die-cutting tool withreference to the so-called steel-strip tools known from printingtechnology, with which any number of shapes can be produced by means ofdie-cutting paper, namely a form of die-cutting from a larger sheet ofpaper or cardboard.

[0029] If one applies such a steel-strip tool die-cutting process to thepossibilities for manufacturing antennas or coils for transponder-likearrangements, the longitudinal shape of the lower blade of thedie-cutting tool, that is the section used to die-cut the shapes intothe double foil 10, would follow the desired shape of the coil orantenna to be manufactured, whereby with respect to the embodiment shownin FIG. 1 and also in FIG. 3, a spiral-shaped, i.e. an inwardly taperedcoil winding has been selected.

[0030] Of course, the antenna's windings and turns can be shapedcompletely differently—for instance, the individual turns of the antennacan follow the outer, possibly rectangular shape of the double foil andcut out specific sections as other assemblies are to be located on thetag or the chip card for instance (e.g. other electronic components,chip card push buttons or the like)—the structure of the die-cuttingtool is always such that the entire winding, in this case a spiral,inwardly tapered winding, is cut into the double foil in a singledie-cutting process.

[0031] A further possibility which exists within this context consistsof designing a die-cutting tool which has dual blades in the die-cuttingzone, consisting of two lower cutting edges displaced minimally fromeach other as suggested by 13 a in FIG. 2. If the entire die-cuttingtool has a spiral shape, a narrow spiral strip 14 is die-cut from thedouble foil 10′ (FIG. 3), which is then removed during the course of theprocessing operation, i.e. it must be removed, leaving a copper oraluminium strip 15 (subject to the selected material) with turns thatare isolated from each other and which is spiral or volute in shape.

[0032] However, the preferred embodiment of the present inventioninvolves working with only one single die-cutting edge 13 and dispensingwith such a direct die-cutting process, an approach which has proven tobe quite successful, also with respect to the required isolatingdisplacement of the individual turns of the coil or antenna produced.The reason for this can be found in the fact that the copper oraluminium foil on the synthetic substrate 12 proves to be relativelysoft in terms of its material response and not at all elastic. Followingthe die-cutting process, that is after the double foil 10 has beenincised or perforated, a phenomenon occurs whereby the perforated copperfoil edges remain separated from each other, while the perforated edgesof the synthetic substrate 12 approach each other again due to theelastic or yielding behaviour of this substrate. This results in a shapesuch as that shown schematically in the greatly magnifiedcross-sectional representation on the right hand side of FIG. 2following the die-cutting procedure and after the die-cutting tool 13has been retracted. The descending die-cutting tool initially cuts thecopper foil, inevitably pressing it slightly apart in order to be ableto physically incise and perforate the double foil 10 at all. At thesame time the edges 11 a, 11 b of the copper foil are pressed downslightly, that is they are slightly deformed, a factor that contributesappreciably to the creation of the separation A between both edges ofthe copper foil. Of course, the synthetic substrate 12 is alsoperforated—although in this case other solutions are conceivable—but thesynthetic film exhibits a different response in terms of its materialproperties, causing its edges or at least those in the zone facing awayfrom the copper foil to approach each other again, that is yield towardeach other, while the distance A between the edges of the copper foilremains the same after the die-cutting process.

[0033] At the same time, this die-cutting process alone results in thecreation of a sufficiently isolating separation A between the individual(spiral) turns of the antenna, with the antenna shape preferably beingfixed in a processing stage that follows the previous one immediatelyand which involves the strip comprising the double foil 10 travellingfurther through the processing machine and having an adhesive filmapplied from below, that is onto the synthetic film substrate. It makessense to leave the (copper) surface of the antenna or coil created inthis way uncovered in order to be able to connect a chip 19 insubsequent processing stages.

[0034] It can be observed that the separation achieved between theindividual turns of the antenna by means of the die-cutting process is afunction of a multiplicity of variables, not the least being the shapeof the die-cutting tool, the thickness and yield characteristics of thesynthetic substrate employed, the thickness and non-elastic behaviour ofits copper or aluminium coating, and the fact as to whether thesynthetic substrate is fully perforated or only incised to a certaindepth with the simultaneous pressing apart of the copper foil edges cutas a result of the die-cutting process. In the latter case, theadvantage is that the turns, which are relatively mobile in relation toeach other when the substrate is fully perforated, but which are alsofixed immediately by means of subsequent bonding, always retain theirshape and their level of separation from each other, making the adhesivefixing step superfluous.

[0035] The entire manufacturing process, which is intended for instanceto be employed to produce tags and which is substantially simplified bythe invention, thus proceeds as suggested schematically in FIG. 4; anappropriately designed automated in-line facility stamps the antennashapes from the continuously fed strip 16 at point B as described above;at point C the individual antennas on the strip 16 are finished byadding individual chip modules being fed from point D, whereby assuggested in FIG. 1, the beginning 17 and end 18 of the stamped antennashape are connected to the corresponding terminal pads of the chipmodule 19, preferably by means of crimping, but possibly also by meansof soldering or other bonding techniques. The strip 16 with the antennasfinished by the addition of the chip module 19 is then conveyed to thelaminating unit E, where processing is completed by the addition ofadditional upper and lower layers 20, 21, 22 by means of adhesive orheating. The final laminated strip 16′ with individual tags positionedalong it can then be dispatched to the user in this form or the tags areseparated from the strip by means of an additional cutting ordie-cutting process.

1. Method for manufacturing a tag encompassing an antenna or coil thatis capable of wirelessly transmitting information to remote receiversand/or receiving information from remote transmitters, a chip oridentification card or a transponder unit or the like, wherein the coilor antenna shape is produced by stamping it from an electricallyconductive flat foil and it is then bonded with additional layersincluding an electronic chip module.
 2. Method in accordance with claim1, wherein the electrically conductive flat foil (copper or aluminiumfoil 11) is arranged on a synthetic film substrate (polyester film 12)and the double foil 10 created in this manner is subjected to adie-cutting process.
 3. Method in accordance with claim 1 or 2, whereina die-cutting tool is used for die-cutting which has a singledie-cutting blade that is similar to a strip steel tool and that matchesthe desired form of the antenna or coil shape and which completelyperforates the upper electrically conductive flat foil and partially orcompletely separates the lower synthetic film substrate, wherein atleast the electrically conductive flat foil consists of a soft,inelastic metal such as copper or aluminium, therefore retaining thedistance (A) created by die-cutting after the die-cutting tool has beenremoved.
 4. Method in accordance with any one of the claims 1 to 3,wherein the die-cutting tool disposes of narrowly-separated, adjacenttwin blades which also stamp out the strip of material to be removedfrom the double foil (10), following the path of the desired antenna orcoil shape.
 5. Method in accordance with any one of the claims 1 to 4,wherein the double foil (10) in the form of a long strip for die-cuttingthe antenna or coil shapes is fed into an automated processing plant andwherein subsequently the beginning and end sections (17, 18) of theantenna shapes are connected to the terminal pads of chips fedseparately and lamination is undertaken using additional surface layers(20, 21, 22) while the double foil strip (16) is being conveyed onward.6. Device for manufacturing a tag encompassing an antenna or coil, achip or identity card, a transponder unit and the like for the purposeof executing the method in accordance with any one of the claims 1 to 5,wherein provision is made for a die-cutting tool with a single or doubleblade (13, 13 a) which stamps out an antenna shape preferably from acontinuously fed double foil of electrically conductive material and asynthetic film substrate, whereby the beginning and end of the antennashape is to be connected to a chip module.
 7. A tag containing anantenna or coil, a chip or identity card, a transponder unit and thelike, wherein one of the layers (20, 21, 22, 16) forming the tag or thechip card is produced from a double foil, consisting of an electricallyconductive flat material and a synthetic substrate, whereby the antennaor coil is stamped into said foil in the form of concentric,electrically isolated turns, the beginning and end section of which isconnected to a chip module.